Bistable Cholesteric Liquid Crystal Displays – Review and Writing Tablets

Summary

Cholesteric liquid crystals (ChLC) were the beginning of this incredible phase of matter – discovered in the late nineteenth century. This chapter describes fundamental modes of operation, their effectiveness, and their unique new capability in analog writing devices created via pressure‐induced flow alignment. There are many ways to switch between cholesteric textures, including stabilizing the scattering Focal conic texture and switching it to a clear homeotropic state to make shutters and using very high pretilt, controlled cell gaps, and polarizers to make bistable displays. ePaper technologies have transformed the user experience and interaction with electronics devices by appealing to the familiar reading experience that reflective displays offer. Writing tablets are a very successful example of the use of ChLC displays that cater to writing as an undeniably essential human activity complementary to reading and still very much dependent on the use of paper.